Init inferencer.

Author: reyoung

python/paddle/v2/__init__.py

@@ -24,12 +24,13 @@
 from . import reader
 import attr
 import pooling
+import inferencer
 import py_paddle.swig_paddle as api
 
 __all__ = [
     'optimizer', 'layer', 'activation', 'parameters', 'init', 'trainer',
     'event', 'data_type', 'attr', 'pooling', 'data_feeder', 'dataset', 'reader',
-    'topology'
+    'topology', 'inferencer', 'infer'
 ]
 
 
@@ -39,3 +40,6 @@ def init(**kwargs):
         args.append('--%s=%s' % (key, str(kwargs[key])))
 
     api.initPaddle(*args)
+
+
+infer = inferencer.infer

python/paddle/v2/inferencer.py

@@ -0,0 +1,54 @@
+import py_paddle.swig_paddle as api
+
+import topology
+from data_feeder import DataFeeder
+import itertools
+import numpy
+
+__all__ = ['InferenceEngine', 'infer']
+
+
+class InferenceEngine(object):
+    def __init__(self, output, parameters):
+        topo = topology.Topology(output)
+        gm = api.GradientMachine.createFromConfigProto(
+            topo.proto(), api.CREATE_MODE_TESTING, [api.PARAMETER_VALUE])
+        for param in gm.getParameters():
+            val = param.getBuf(api.PARAMETER_VALUE)
+            name = param.getName()
+            assert isinstance(val, api.Matrix)
+            val.copyFromNumpyMat(parameters.get(name))
+        self.__gradient_machine__ = gm
+        self.__data_types__ = topo.data_type()
+
+    def iter_infer(self, reader, reader_dict=None):
+        feeder = DataFeeder(self.__data_types__, reader_dict)
+        out_args = api.Arguments.createArguments(0)
+        self.__gradient_machine__.start()
+        for data_batch in reader():
+            yield self.__gradient_machine__.forwardTest(
+                feeder(data_batch), out_args, api.PASS_TEST)
+        self.__gradient_machine__.finish()
+
+    def iter_infer_field(self, field, **kwargs):
+        for result in self.iter_infer(**kwargs):
+            yield [each_result[field] for each_result in result]
+
+    def infer(self, field='value', **kwargs):
+        retv = []
+        for result in itertools.izip(
+                self.iter_infer_field(
+                    field=field, **kwargs)):
+            retv.append(numpy.concatenate(result))
+        return retv
+
+    def default_reader_dict(self):
+        reader_dict = dict()
+        for i, tp in enumerate(self.__data_types__):
+            reader_dict[tp[0]] = i
+        return reader_dict
+
+
+def infer(output, parameters, reader, reader_dict=None, field='value'):
+    inferer = InferenceEngine(output=output, parameters=parameters)
+    return inferer.infer(field=field, reader=reader, reader_dict=reader_dict)